Currently on Quickplay/Competitive.
Mei and McCree can stun a target then hold down left click and headshot TWICE before the stun runs out.
With these changes, they can only headshot ONCE before the stun runs out.
McCree
Flash+ThrowRecovery+Headshots
0.35sec + 0.42sec = 0.77sec
It was reduced from 0.85sec, to 0.7sec.
Mei
Freeze+IcicleCharge+FireDelay+IcicleCharge
0.35+0.8+0.35 = 1.5sec
It was reduced from 1.5sec, to 1.3sec.